Summary of Marine environment

2011

Australia's oceans and coastal marine ecosystems are overall in good condition and have experienced only gradual decline, although there are many local coastal areas where ecosystems are in poor or very poor condition as a result of local pressures. Indeed, some of the world's worst examples of impacts from pollution can be found in Australian waters. Australia is world leading in many areas of marine management, but low levels of pressures have allowed environmental resilience to remain high in many regions. Now, there are strong signals that many of our marine systems and resources have reached their finite limit and pressures are building to levels where impacts can be easily seen in many of the regions.

Nearshore development is proceeding quickly, replacing vegetated landscapes with hard surfaces that interrupt wetland functions and estuarine flows. Land-based sources of pollution and expanding pressure on coastal lands continue to be a significant concern, despite strong improvements in land-use planning and the management of many point sources of pollution. Fishing has reduced most populations of sought-after species to low levels, mainly in previous decades. The maintenance of these low population levels by present-day management policies probably has significant flow-on consequences for the resilience and persistence of marine biodiversity in all inshore waters. The major looming threat for our oceans and coastal waterways is the changing global climate, which is creating significant changes in ecosystems, biodiversity, shorelines and coastal lands. It threatens our wealth generation from the oceans, and the existence of our coral reefs at their present-day scale and grandeur. A proliferation of oil and gas exploration and extraction, together with the new energy and water systems, and other shoreline industries, brings not only important initiatives in wealth generation, but also a major new set of risks to our waters that will require intensive strategic and regional management.

Regionally, the north-west is beginning to come under intense development pressure from the resource extraction sectors (oil and gas, mining, fishing, shipping). The marine values and assets of the north region remain relatively pristine, although even there, mining and river damming are growing pressures. The south-east region remains under the greatest stress, with a legacy of impacts from a wide variety of sources, and is suffering the greatest impacts from changing climate—the East Australian Current is changing its pattern of extension into Tasmanian waters with the intensification of gyres and increases in temperature.

The interaction of accelerating changes in the climate with existing land uses, fishing systems, shoreline industries and new risks is presenting ocean management with unprecedented challenges. There is a plethora of responses to this situation, many of which are achieving good outcomes; some are reducing pressures, and holding ecosystems and biodiversity in good condition. However, the evidence is that our management systems are still too fractured, weakly coordinated and poorly integrated to halt the accelerating degradation of the unique values of our oceans and coastal ecosystems. The early signals of such decline are now evident across a number of areas of our coastal waters. Perhaps the most critical challenge of all now confronts us—our ability to design and deliver good, effective and efficient governance to address the known threats and accelerating risks to our unique marine environment.

Mackay R, Wienecke B (2011). Overview: Summary of Marine environment. In: Australia state of the environment 2011, Australian Government Department of the Environment and Energy, Canberra, https://soe.environment.gov.au/theme/overview/marine-environment/topic/summary-marine-environment, DOI 10.4226/94/58b65510c633b